 /*******************************************************************************
  * Copyright (c) 2005, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.menus;

 import org.eclipse.core.commands.common.NotDefinedException;
 import org.eclipse.jface.util.PropertyChangeEvent;
 import org.eclipse.jface.util.Util;

 /**
  * <p>
  * A menu in a menu bar, a context menu or a pulldown menu attached to a tool
  * item.
  * </p>
  * <p>
  * Clients may instantiate this class, but must not extend.
  * </p>
  * <p>
  * <strong>PROVISIONAL</strong>. This class or interface has been added as
  * part of a work in progress. There is a guarantee neither that this API will
  * work nor that it will remain the same. Please do not use this API without
  * consulting with the Platform/UI team.
  * </p>
  * <p>
  * This class will eventually exist in <code>org.eclipse.jface.menus</code>.
  * </p>
  *
  * @since 3.2
  */
 public final class SMenu extends MenuContainer {

     /**
      * The property for a property change event indicating that whether the
      * label for this menu has changed.
      */
     public static final String PROPERTY_LABEL = "LABEL"; //$NON-NLS-1$

     /**
      * The label for this menu. This label is displayed to the user. It may be
      * <code>null</code>, if it appears only as an icon.
      */
     private String label;

     /**
      * Constructs a new instance of <code>SMenu</code>.
      *
      * @param id
      * The identifier of the menu to create; must not be
      * <code>null</code>
      */
     SMenu(final String id) {
         super(id);
     }

     /**
      * <p>
      * Defines this menu by indicating the label. The location is optional. The
      * defined property automatically becomes <code>true</code>.
      * </p>
      *
      * @param label
      * The label for this menu; may be <code>null</code>.
      * @param location
      * The location in which this menu will appear; may be
      * <code>null</code>.
      */
     public final void define(final String label, SLocation location) {
         define(label, location, null);
     }

     /**
      * <p>
      * Defines this menu by indicating the label. The locations and dynamic menu
      * are optional. The defined property automatically becomes
      * <code>true</code>.
      * </p>
      *
      * @param label
      * The label for this menu; may be <code>null</code>.
      * @param location
      * The location in which this menu will appear; may be
      * <code>null</code>.
      * @param dynamic
      * The class providing dynamic menu elements to this group; may
      * be <code>null</code>.
      */
     public final void define(final String label, SLocation location,
             final IDynamicMenu dynamic) {
         final SLocation[] locations;
         if (location == null) {
             locations = null;
         } else {
             locations = new SLocation[] { location };
         }
         define(label, locations, dynamic);
     }

     /**
      * <p>
      * Defines this menu by indicating the label. The locations and dynamic menu
      * are optional. The defined property automatically becomes
      * <code>true</code>.
      * </p>
      *
      * @param label
      * The label for this menu; may be <code>null</code>.
      * @param locations
      * The locations in which this menu will appear; may be
      * <code>null</code> or empty.
      * @param dynamic
      * The class providing dynamic menu elements to this group; may
      * be <code>null</code>.
      */
     public final void define(final String label, SLocation[] locations,
             final IDynamicMenu dynamic) {
         if ((locations != null) && (locations.length == 0)) {
             locations = null;
         }

         setDefined(true);
         setLocations(locations);
         setDynamic(dynamic);
         setLabel(label);
     }

     /**
      * Returns the label for this menu. A menu does not need a label if its is
      * simply a pulldown menu on a tool item.
      *
      * @return The label for this menu; may be <code>null</code>.
      * @throws NotDefinedException
      * If the handle is not currently defined.
      */
     public final String getLabel() throws NotDefinedException {
         if (!isDefined()) {
             throw new NotDefinedException(
                     "Cannot get the label from an undefined menu"); //$NON-NLS-1$
 }

         return label;
     }

     /**
      * Sets the label that should be displayed for this menu. This will fire a
      * property change event if anyone cares.
      *
      * @param label
      * The new label for this menu; may be <code>null</code>.
      */
     protected final void setLabel(final String label) {
         if (!Util.equals(this.label, label)) {
             PropertyChangeEvent event = null;
             if (isListenerAttached()) {
                 event = new PropertyChangeEvent(this, PROPERTY_LABEL,
                         this.label, label);
             }
             this.label = label;
             firePropertyChangeEvent(event);
         }
     }

     /**
      * The string representation of this menu -- for debugging purposes only.
      * This string should not be shown to an end user.
      *
      * @return The string representation; never <code>null</code>.
      */
     public final String toString() {
         if (string == null) {
             final StringBuffer stringBuffer = new StringBuffer ();
             stringBuffer.append("SMenu("); //$NON-NLS-1$
 stringBuffer.append(id);
             stringBuffer.append(',');
             stringBuffer.append(label);
             stringBuffer.append(',');
             try {
                 stringBuffer.append(dynamic);
             } catch (final Exception e) {
                 // A bogus toString() in third-party code. Ignore.
 stringBuffer.append(e.getClass().getName());
             }
             stringBuffer.append(',');
             stringBuffer.append(defined);
             stringBuffer.append(')');
             string = stringBuffer.toString();
         }
         return string;
     }

     /**
      * Makes this menu become undefined. This has the side effect of changing
      * the label, locations and dynamic class to <code>null</code>.
      * Notification is sent to all listeners.
      */
     public final void undefine() {
         string = null;

         setLabel(null);
         setDynamic(null);
         setLocations(null);
         setDefined(false);
     }
 }

